The International Standards ISO/IEC 11172-1 (Systems) ,ISO/IEC 11172-2 (Video) and ISO/IEC 11172-3 (Audio) describe the coding of moving pictures and associated audio for digital storage media. This set of standards is more commonly known as MPEG-1 (Moving Pictures Expert Group).
MPEG defines the format of a compressed data stream and proposes ways in which it can be decoded (decompressed and played back). However, there are no constraints on how streams are produced so that encoders are free to implement their own algorithms to gain a competitive edge.
The widespread use of video material on the Internet is constrained by low speed communication channels and the limited space available on user PCs and Web page servers. Compression of digitised video reduces the volume of data dramatically but resulting file sizes are still prohibitive (for the Internet environment). The available solutions either produce large files, or compromise the quality of video and/or audio, or reduce the picture rate to achieve their goals.
There is therefore a requirement for a method which produces good quality, synchronised video and audio which can be played back using commercially available software decoders at 25 frames per second (fps) i.e. like watching small-screen TV--but all at very low bandwidth.